This fallacy occurs when it is assumed that because one event (B) happened after another event (A), event A must have caused event B. However, just because two events are correlated in time does not necessarily mean one caused the other. To avoid committing this fallacy, the argument must provide an explanation for how and why event A could have caused event B, rather than just stating the events happened in a certain order.

1. Post hoc (also called false cause)
This fallacy gets its name from the Latin phrase "post hoc, ergo propter
hoc," which translates as "after this, therefore because of this."
Definition: Assuming that because B comes after A, A caused B. Of
course, sometimes one event really does cause another one that comes
later—for example, if I register for a class, and my name later appears on
the register, it's true that the first event caused the one that came later. But
sometimes two events that seem related in time aren't really related as
cause and event. That is, correlation isn't the same thing as causation.
Examples: "The Prime Minister raised taxes, and then the rate of violent
crime went up. The PM is responsible for the rise in crime." The increase
in taxes might or might not be one factor in the rising crime rates, but the
argument hasn't shown us that one caused the other.
Tip: To avoid the post hoc fallacy, the arguer would need to give us some
explanation of the process by which the tax increase is supposed to have
produced higher crime rates. And that's what you should do to avoid
committing this fallacy: If you say that A causes B, you should have
something more to say about how A caused B than just that A came first
and B came later!
Summer Task: Write a brief evaluation (100-150 words each) of the
strength of each of the following post hoc arguments.
On the 26th July 2008, the Guardian selected the film The Dark Knight as
film of the week. The Dark Knight was the most watched film at the
cinema in the following week.
The summer was hot. Fewer people than usual took foreign holidays.
It is easy and convenient to download music from the internet. A wide
range of music is available on line. Fewer people than ever are buying
CDs.
Carla Bruni is a tall, attractive, former model. Nicholas Sarkozy married
Carla Bruni in 2007.
Arsenal won 86% of games in which Cesc Fabregas played. Fabregas
was injured for most of the season and Arsenal finished fourth.